High molecular weight polysulfates

ABSTRACT

DETERGENT ACTIVE MATERIALS WHICH ARE EFFECTIVE IN THE ABSENCE OF PHOSPHATE BUILDERS COMPRISE HIGH MOLECULAR WEIGHT POLYSULFATES OF THE FOLLOWING STRUCTURE:   CH3-(CH2)M-C(-CH2-O-Z)2-(CO)X-(CH(-O-Z))Y-C(-CH2-O-Z)2-   (CH2)N-CH3   IN WHICH M AND N ARE INTEGERS FROM 0 TO 40 AND THE SUM OF M AND N IS FROM 15 TO 40, X AND Y ARE INTEGERS FROM 0 TO 1 AND THE SUM OF X AND Y IS 1, Z IS H OR -SO3Q IN WHICH Q IS A WATER SOLUBLE, SALT-FORMING CATION, AND AT LEAST 3 AND PREFERABLY 4 Z&#39;&#39;S ARE -SO3Q.

' itd S e Pa en ABSTRACT OF THE DISCLOSURE Detergent active materials which are elfective in the absence of phosphate builders comprise high molecular weight polysulfates of the following structure:

in which m and n are integers from 0 to 40 and the sum ofm and n is from to 40, x and y are integers from 0 to 1 and the sum of x and y is 1, Z is H or -SO Q in which Q is a'water-soluble, salt-forming cation, and at least 3 and preferably 4 Zs are SO Q.

BACKGROUND OF THE INVENTION I Field of the invention The present invention is concerned with novel synthetic'detergents and more particularly with novel polysulfatesywhich are suitable as biodegradable and phosphate-free detergent compositions.

Increased concern with water pollution has producedsignificant changes in household detergents. Initially, major emphasis has been placed on producing biodegradable surface active "components for detergents. The shift to linear surface active materials, including linear alkyl benzene sulfona'tes (LAS) and alpha olefin sulfonates, etc., has reduced pollution attributed to nonbiodegradability. However, the above-mentioned surface active materials are hot adequate in terms of soil removal in the absence of phosphate builders. Increasing evidence appears to indicate that phosphates contribute to the growth of algae in the nations streams and lakes. This algae growth poses a seriouspollutionthreat to the maintenance of clear good domesticwater supplies.

It is therefore desirable to produce surfactant materials which function well inthe absence of phosphate builders and possess biodegradable characteristics.

. Prior art In' the past, certain polysulfates derived from higher molecular weight polyalcohols have been disclosed.

U.S. Pat. 2,014,782 discloses materials particularly suitablefor use in textile manufacture which are disul' fates derived from unsaturated fatty alcohols from sperm oil.- The unsaturated alcohols are reacted with sulfuric acid, hydrolyzed by boiling water, separated from the water and sulfated with chlorosulfonic acid. The product isnsually a 1,9-octadecane disulfate.

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U.S. Pat. 2,091,956 discloses disulfates which are prepared from vicinal hydroxy alkyl materials of. from 12 to 38 carbon atoms. These materials, glycols, are obtained by the sodium reduction of the esters of high fatty acids followed by hydrogenation of the resulting acyloins to glycols. After sulfation of the glycols, the resulting materials after neutralization are said to be useful as detergents, wetting agents and emulsifying agents.

As may be seen, the materials of the above references are either secondary sulfates or a combination of a primary and a secondary sulfate. The preparation of the secondary sulfates is usually complicated by the propensity of the materials to dehydrate when sulfation by S0 or sulfuric acid is attempted, producing large amounts of unsaturated materials and resulting in low yields of detergents. In order to achieve substantial yields of de-.

sired product, sulfation with chlorosulfonic acid in a complexing solvent such as ether is necessary.

SUMMARY OF THE INVENTION Novel compounds which may be suitably employed as phosphate-free detergents are provided. These compounds are of the following general structure in which m and n are integers from 0 to 40 and the sum of m and n is from 15 to 40, x and y are integers from 0 to 1 and the sum of x and y is 1, Z is H or -SO Q in which Q is a water soluble, salt-forming cation, and at least 3 and preferably 4 ZS are --SO Q. Q is preferably an alkali metal cation and is most preferably Na+. Preferably the sum of m and n will be from 20 to 35.

The detergent compounds are prepared by the sulfation of polyhydroxy intermediates which are derived from higher ketonesthat is, ketones of from about 20 to 45 carbon atoms, preferably about 25 to 35 carbon atoms.

The higher ketones which are employed are preferably linear and may be derived by conventional techniques from fatty acids. Thus, they may be prepared by the thermal decarboxylation of the fatty acids. By this procedure the acids are heated in the presence of barium, calcium or thorium oxides or hydroxides, or the corresponding barium, thorium or calcium salts of the acid are heated, resulting in the loss of one carboxyl group and resulting in the preparation of a ketone having one less carbon atom than the pair of original condensed acid or salt molecules. Mixtures of various acids may be employed with the resulting carbonyl group being at any position on the chain. Ketones prepared by other techniques such as the hydration of dialkyl alkynes, the oxidation of internal olefin, or the rearrangement of 1,2-glycols may also be employed.

By a preferred procedure in producing the purified pentahydroxy alkyl material, the high molecular weight ketone is reacted with formaldehyde in acetic acid in the presence of a catalytic amount of a mineral acid to form a crude reaction mixture. This mixture is then reacted with acetic anhydride and sulfuric acid in order to destroy the considerable amount of formal which;

forms during the reaction. The resulting polyester, which contains a carbonyl group, is reduced by conventional reduction techniques (e.g., LiAlH H /cat, etc.) to form a polyol containing 3 to 5 hydroxy groups. Direct sulfation of this material by conventional methods (e.g., with S sulfuric acid, oleum, or chlorosulfonic acid) produces a detergent precursor having from 3 to sulfate groups per molecule, the major constituent containing about four sulfate groups per molecule.

Neutralization of the sulfates prepared by the above techniques with water-soluble, salt-forming cations yields the desired product which has highly desirable detergent properties. Thus the sulfated products may be neutralized with aqueous basic solutions containing compounds such as hydroxides, carbonates, and acids of the alkali metals, alkaline earth metals, ammonium and other water-soluble salt-forming cationic agents.

The polyol intermediates can, if desired, be isolated and are suitably employed in other organic preparations. For example, they may be employed as cross-linking agents in polyurethane compositions giving internal plasticization as well as rigidification. By the hydrolysis or saponification of the ester groups the compounds may be isolated as the mono ketone tetraol. The pentaol form can be obtained by reduction of the ketone polyester. The materials will have the following general formula OH OH (311, 0 OH (3H CH (CH2)m( J (1-I) J(CH )nCH In general, when the compounds of the present invention are formulated as detergent compositions, additional compatible ingredients may be incorporated therein to enhance their detergent properties. Such ingredients may include, but are not limited to, anticorrosion, antiredeposition, bleaching and sequestering agents, optical whiteners and certain organic and inorganic alkali and alkaline earth salts, such as inorganic sulfates, carbonates, or borates, and organic salts of the amino polycarboxylic acids; e.g., trisodium salt of nitrilo triacetic acid, tetrasodium salt of ethylene diamine tetraacetic acid, etc. In addition, other builder materials such as the salts of polymeric carboxylic materials such as the copolymers of ethylene and maleic anhydride may be employed as builder additives.

Surprisingly, the novel compounds of the present invention exhibit high detersive characteristics even in the absence of phosphate builders. In particular, formulations containing sodium or potassium sulfates as the major active ingredient are preferred. This is unexpected, in view of the majority of household heavy duty detergent compositions which require the presence of large amounts of phosphate builders in order to exhibit satisfactory detergency levels.

The following examples illustrate the preparation of the detergent sulfate compounds and the polyol precursors of this invention. The examples are intended to be only illustrative and are not limiting.

EXAMPLE 1.-PR'EPARATION OF 3l-CARBON KETONE A mixture of 40 g. of palmitic acid and g. of magnesium oxide was charged to a 1-liter 4-necked flask fitted with a stirrer, condenser, thermometer, dropping funnel, and heating mantle. The mixture was heated to 330340 C. Steam was passed through the condenser throughout the reaction. A total of 216 g. of additional palmitic acid was melted and added through the dropping funnel in about 10 g. portions every 10-15 minutes. A vigorous reaction ensued after each addition. The acid was kept molten by heating the dropping funnel with an infrared lamp.

The mixture was hand stirred occasionally and heated at 330340 C. for a total of 10 hours.

The mixture was then cooled to C. and a 250 ml. portion of a solution of 50 ml. of concentrated sulfuric acid in 5 00 ml. of water was added. The mixture was refluxed, cooled, and decanted. It was then refluxed twice with l-liter portions of water, once with 1 liter of 1 N sodium hydroxide, and three times more with l-liter portions of water. The solid material was filtered from the solution, crushed, dried, and recrystallized from 1 liter of a 2:1 mixture of benzene and alcohol. A total of 182 g. of a C linear ketone was recovered in a 77% yield.

EXAMPLE 2.-PREPARATION O'F POLYADCOHOL To a 500 ml. 3-necked flask fitted with a stirrer, condenser, thermometer, and nitrogen inlet was added 30 g. of paraformaldehyde (1.0 mol equivalent of formaldehyde), 170 ml. of glacial acetic acid, and 1.4 ml. of concentrated sulfuric acid. The mixture was stirred and heated to 9095 C. under a nitrogen atmosphere. After about 15 minutes, 45 g. (0.1 mol) of the ketone prepared in Example 1 was added to the reaction flask. The mixture was heated at -110 C. for six hours, an additional.

0.3 ml. of sulfuric acid was added, and heating continued for an additional three hours.

After cooling the reaction mixture to room temperature, 200 ml. of ether was added. The solution was extracted with several 100-ml. portions of water, two 100- ml. portions of 0.5 N sodium hydroxide, then with several portions of water until neutral. The remaining ether solution was dried over sodium sulfate, decanted, and evaporated to dryness. A 6O g. yield was recovered.

In order to destroy the formal which formed during the reaction, 59 g. of the above mixture was heated to 80 C. for 1 /2 hours in ml. acetic anhydride containing 2 ml. of sulfuric acid. This workup was the sameas above.

EXAMPLE 3.REDUCTION THE POLYESTER To a 2,000-ml. 3-necked flask fitted with a stirrer, condenser, thermometer, dropping funnel, and nitrogen inlet was added 12 g. of lithium aluminum hydride. 750 ml.

of anhydrous ether was added through the addition funnel in about 5 minutes. A solution of 60 g. of the tetraester product of Example 2 in 250 ml. ether was added dropwise over a period of 45 minutes. The reaction flask was cooled in an ice bath so that the reaction temperature remained below 25 C. After the addition was completed,

the reaction mixture was stirred at room temperature.

for 24 hours.

The product was transferred to a beaker and cooled in an ice-acetone bath. A freshly prepared saturated solution. of anhydrous powdered sodium sulfate was added about 1 ml. at a time with stirring until evolution of gas ceased. I

The solid material was filtered from the reaction mixture, dried, ground, and slurried with a mixture of 1500 ml. of dilute acid and 1500 ml. ether. The ether layer was decanted and combined 'with the ether filtrate from, the reaction. This process was repeated until no. more,

solid was obtained by the ether extraction of. the slurry.

EXAMPLE 4.-PREPARATION OF POLYSULPATE layer. The remaining water solution of the'desired'poly-' sulfate was diluted to a known volume and aliquots were removed for a Hyamine titration 'to determine the degree of sulfation.

( 3 8:? method of House and Darragh, Anal. Chem.; 26,1492

Detergency of the compounds of..the present invention is measured by its ability L'to' remove natural sebum soil from cotton cldth." By this method,-small swatches of cloth, soile d by rubbing. Qverface and neck, are-washed with testsolutions of detergents in a miniature laboratory washer, and the reflections of the various cloths measured and compared. The resultsobtained are expressed as relative detergency value V The relative detergency value is obtainedby comparing and correlating the reflectance value results from the test solution with the results from two defined standard solutions.

The two standard solutions are selected to represent a detergent system exhibiting relatively high detersive characteristics.

By testing experimental solution against the standardized solutions on cotton cloth soiled with natural sebum soil, the results can be accurately correlated. The two standard solutions were prepared:

Formulation for the low detersive standard (control A) Four test solutions were prepared from each formulation. The first two consisted'of l and 2 g. portions, respectively, of the formulation dissolved in 1 liter of50 p.p.m. hard water. The'third-an'd fourth consisted of 1 and 2 g. portions, respectively, of theformulation dissolved in 1 liter of 180 p.p.m. hard water. 1

The miniature laboratory washer used was so constructed that the two standard formulations and two test formulations could be used'to wash different parts of "the same swatch. This arrangement ensured that all four formulations were working on identical soil (natural facial soil). Relative detergency (RD) values were -calculated from soil removals ,(SR), according to the equation:

Percent SR -Percent SR A RD= Percent SHOW), -Pereent s Conti-ol A For comparison purposes one formulation contained LAS as a detergent active and sodium triphosphate. The remainder of the formulation was the same as above except that the sodium sulfate content was 19%.

Detergency test results obtained on a variety of the polysulfates and the LAS formulations are given in the table following. These data clearly show that the polysulfates and particularly the material derived from a C ketone in the absence of any builder are superior to the unbuilt LAS formulation and are equivalent to a phosphate built LAS formulation in hard water. These results are unexpected.

RELATIVE DETERGENOY OF POLYSULFATES Test materials Relative detergency ratings Carbon ppm. H 0 180 p.p.m. H2O atoms in Sample ketone 0.1% cone. 0.2% cone. 0.1% cone. 0.2% cone.

Linear alkylbenzene sulfonate (unbuilt LAS) 2. 8 4.4 0.9 2.2 Linear alkylbenze sulionate plus phosphate (40% of Nazsm replaced by sodium tripolyphosphate) 6. 3 6. 6 2. 4 5. 8 Polysulfate 1 31 2 4.3 2 5. 3 a 3. 7 a 4. 8

D03. 35 3.1 4. 8 D0. 39 2. 2 3.2 D03- 43 l. 8 2. 9 D01- 27 3 3.0 8 4. 3

V 1 Prepared by the described method.

' 2 Average of 3 runs. 3 Average of 2 runs.

Formulation for the high detersive standard (control B) Ingredient: Weight percent Linear alkyl benzene sulfonate (LAS) 7.5 Tallow alcohol sulfate 10 Sodium Triphosphate 47.5 Water 10 Sodium sulfate 13 Sodium silicate 5 Carboxymethylcellulose 1 high molecular weight polysulfates formulated in the following manner:

Ingredient: Weight percent Active detergent 25 Sodium sulfate 59 Carboxymethylcellulose 1 Sodium silicate 7 Water 8 LAS comparative formulations were also prepared in the same way.

Thus, the polysulfates of this invention find substantial use in various built and unbuilt, liquid or solid detergent compositions.

In addition to their use as sulfate detergent precursors, the polyols of this invention, with or without the presence of carbonyl groups, are useful as cross-linking agents, solvents, etc.

While the character of this invention has been described in detail with numerous examples, this has been done by way of illustration only and without limitation of the invention. It will be apparent to those skilled in the art that modifications and variations of the illustrative examples may be made in the practice of the invention within the scope of the following claims.

We claim:

1. As a composition of matter a polysulfate of the following formula in which m and n are integers from 0 to 40; the sum of m and n is from 15 to 40; x and y are integers from 0 to l; the sum of x and y is 1; Z is H or SO Q is selected from the group consisting of alkali metal, alkaline earth metal and ammonium cations; and at least 3 Zs are -SO Q.

2. The composition of claim 1 in which the sum of m and n is from 20 to 35.

3. The composition of claim 1 in which y is 1.

'4. The composition of claim 1 in which x is 1.

5. The composition of claim '2 in which 4 Zs are SO Q.

6. The composition of claim 2 in which Q is an alkali metal cation.

7. The composition of claim 6 in which the alkali metal lo cation is Na Refe -ences Cited 7 UNITED STATES PATENTS 2,979,521 4/1961 Gray 260-458 2,265,194 12/1941 'Reibnitzet al. 260- 158 LEON ZITVER, Primary=Examiner L. B. DE CRESENTE', AssistantExaminer US. 01. 11; 252-161, 353, 364; 260594, 638 B, 77.5 A 

